In an information environment of an office, with the spread and adoption of computers, software, and networks, sharing of information and rapid processing thereof has become possible. Digitization of information is excellent from the viewpoint of storage, accumulation, search, and the like of the information. However, paper is a superior medium on which to display (in particular, perspicuity) and communicate information. For this reason, the amount of paper used is increasing even though digitization of information is growing. On the other hand, reduction of energy consumption represented by CO2 emission is an urgent need in various fields. If the paper medium used for a temporary display or communication of information may be recycled, it may significantly contribute to the reduction of energy consumption.
If an image formed on the paper medium is erased, recycling of the paper medium is possible. Physical properties of such an erasable decoloring toner used on the paper medium are described in Japanese Patent No. 5213939. A decoloring toner allows reuse of paper sheets since it is possible to erase, i.e., decolor and thus render non-visible to the human eye, the image printed on the paper. This process is known in the art as “decoloring.” An apparatus which may use an ordinary non-decoloring toner with such a decoloring toner in one image forming apparatus is needed.